Check out all your LFS.
Good ones sell all kinds of nice corals, but some of them also have frag tanks with corals that breed in their system.
There is one store around me that I can get soft corals (zoas, shrooms, etc) for 1$ per polyp, or 10$ for a rock with about 20-30 polyps on it. There is another LFS that sells nice sized frags of various soft corals for 15$, reasonable for the size of the frags.
I live in a city not 1/10 the size of NYC, so I'm sure you can find a nice LFS, but it does take some looking around to find good ones.